If you want to test mobile resolution, you can go to editor view, with code on the left, and drag the vertical bar around to test different screen widths.

I like the video and the descriptions that fade in when you mouse over a guitar. However, for me at least, one of the guitars was placed behind the form, which made reading the text difficult. I am using a 1280x1024 monitor in case that helps.

One of the great tools Chrome provides in its dev tools is the ability to simulate different device widths. Press f12 (or right-click >> “inspect”) and click the small tablet icon on top left of dev tools window. Really useful!